Shaving apparatus

Abstract

A shaving apparatus includes at least one cutting unit having an inner cutter rotationally drivable with respect to an outer cutter by driving shaft of a driving device. The driving shaft exerts a prestress force on the inner cutter in the direction of the outer cutter. During cutting of a hair, the hair exerts a cutting force on the inner cutter directed opposite the driving force. The driving shaft bears axially on the outer cutter via at least one driving surface of a coupling element which is rotationally drivable. The inner cutter includes at least one driven surface for cooperating with the driving surface for exerting the driving force. The direction of the driving force is substantially perpendicular to the driving surface and the driven surface.

1. A shaving apparatus with a housing and at least one cutting unit which can be pivotably and resiliently pressed in with respect to the housing, said cutting unit comprising an outer cutter and an inner cutter that can be driven into rotation with respect to the former, said inner cutter being provided with cutting elements with cutting edges, while said outer cutter is provided with hair trap openings bounded by cutting edges for cooperating with the cutting edges of the cutting elements for the cutting of hairs, wherein during cutting of a hair a cutting force is exerted by the hair on the inner cutter, and a plane through the totality of cutting edges defines a cutting plane, said shaving apparatus being further provided with a drive device having a drive shaft for driving the inner cutter, which drive device during cutting of a hair exerts a driving force on the inner cutter, while the drive shaft exerts a prestress force in the direction of the outer cutter, wherein
 the drive device comprises only one coupling member that can be driven into rotation and that is provided with at least one driving surface, 
 the drive shaft axially supporting the inner cutter by means of the coupling member and driving the coupling member into the rotation, 
 the inner cutter is provided with at least one driven surface cooperating with the driving surface for exerting the driving force on the inner cutter, the direction of said driving force being substantially perpendicular to the driving surface and the driven surface, and 
 snaps hooks are provided for fastening the coupling member to the inner cutter, wherein the snap hooks have arm portions and hook portions, the hook portions extending from the arm portions toward a center of the coupling member for hooking onto a coupling bush located around a center of the inner cutter, the coupling bush extending away from a carrier for the cutting elements, and wherein the arm portions, in a direction from the coupling member to the inner cutter, point toward the center of the coupling member. 
 
     
     
       2. The shaving apparatus as claimed in  claim 1 , further comprising means for obtaining a small contact pressure between the cutters. 
     
     
       3. The shaving apparatus as claimed in  claim 2  wherein
 the carrier is provided with the driven surface, 
 the coupling member is coupled to said carrier, the carrier being movable in axial direction with respect to the coupling member, while said coupling member can be coupled to the drive shaft and is provided with the driving surface, and 
 the means for obtaining a small contact pressure between the cutters are present between the carrier and the coupling member. 
 
     
     
       4. The shaving apparatus as claimed in  claim 3 , wherein said means are formed by centrifugal elements which are enclosed between a pressure surface of the carrier and a surface of the coupling member that is directed radially outwards and obliquely towards the carrier. 
     
     
       5. The shaving apparatus as claimed in  claim 4 , wherein the coupling member is provided with a cam, and the pressure surface of the carrier is directed obliquely towards the coupling member viewed in a direction opposed to the drive direction, such that the centrifugal elements lie enclosed between said cam and the sloping pressure surface. 
     
     
       6. The shaving apparatus as claimed in  claim 1 , wherein the driving surface and the driven surface cooperating therewith have mutually corresponding helical shapes. 
     
     
       7. A shaving apparatus comprising:
 an inner cutter having a driven surface and a cutter for cutting a hair; 
 an outer cutter having an opening for receiving the hair which exerts a cutting force on the inner cutter during cutting of the hair; 
 a coupling member having a driving surface; 
 a drive shaft which is configured to drive the coupling member so that the driving surface of the coupling member drives the driven surface of the inner cutter with a driving force; and 
 snaps hooks for fastening the coupling member to the inner cutter, wherein the snap hooks have arm portions and hook portions, the hook portions extending from the arm portions toward a center of the coupling member for hooking onto a coupling bush located around a center of the inner cutter, the coupling bush extending away from a carrier for the cutter of the inner cutter, and wherein the arm portions, in a direction from the coupling member to the inner cutter, point toward the center of the coupling member. 
 
     
     
       8. The shaving apparatus of  claim 7 , wherein the coupling member has a profiled cavity for receiving a coupling head of the drive shaft so that the coupling member is directly driven into rotation by the drive shaft. 
     
     
       9. The shaving apparatus of  claim 7 , wherein the driving surface of the coupling member and the driven surface of the inner cutter have mutually corresponding helical shapes.